1. Field of the Invention
The present invention relates to power tools, such as power grinders for polishing, abrading or cutting workpieces, having improved switch devices for starting and stopping the power tool motors.
2. Description of the Related Art
A known power grinder is shown in FIG. 10 and is generally indicated by reference numeral 41. The grinder 41 comprises a substantially cylindrical housing 42 and a handle 43 connected to the rear end of the housing 42. A motor 49 is disposed centrally within the housing 42 and serves to drive a spindle 44 that downwardly extends from the front end of the housing 42. A grinding disk 45 is mounted on the spindle 44.
A grip portion 46 and a switch device 47 are mounted on the handle 43. The switch device 47 includes a switch circuit that is connected between the motor 49 and a power supply cable 48. The power supply cable 48 extends outward from the rear end of the handle 43 for connection with a power source. The handle 43 has a joint portion 43a that is joined to the housing 42 and that has a substantially cylindrical configuration corresponding to the configuration of the housing 42. The grip portion 46 is adapted be grasped with one hand of an operator, and therefore, the grip portion 46 has a configuration suitable for hand-held operation. More specifically, the grip portion 46 has a substantially cylindrical configuration that has a diameter smaller than the housing 42. The switch device 47 has an operation member 47a that can pivot about a pivotal axis 47b like a seesaw so as to open and close the switch circuit. In addition, the position of the switch device 47 is determined such that the operator can press either side of the operation member 47a with respect to the pivotal axis 47b so as to turn on and off the switch circuit while he grasps the grip portion 46.
However, with the known power grinder 41, the switch device 47 may be accidentally turned on an off, because the operation member 47a can be freely accessed.